The present invention relates to a composition for use in the care of contact lenses, and the like, and more particularly, relates to a cleaning solution for use with contact lenses.
Contact lenses are subjected to the ocular environment for long periods of time each day. As a result of being in contact with the tear film and ocular debris, lenses have a tendency to build up surface deposits. The deposit may be formed from endogenous materials, such as proteins, lipids and mucins, but also may be the result of exogenous materials, such as cosmetic ingredients. To ensure comfortable wear and good vision, these surface deposits must be removed periodically, usually once a day for rigid gas permeable lenses and daily wear soft hydrogel lenses. For flexible wear lenses the cleaning may be less frequent.
Contact lens cleaners can be classified into two categories, primary, or xe2x80x9cdaily cleanersxe2x80x9d and secondary, or xe2x80x9cadjunctxe2x80x9d cleaners. The daily cleaners are surfactant based and are formulated to target the soils most commonly found on either soft hydrogel lenses or rigid lenses. The adjunct cleaners are generally enzyme based and target proteinaceous matter. These enzyme cleaners are usually recommended for weekly use with soft hydrogel lenses. However, more recently, enzyme treatment of rigid lenses has been gaining favor.
The contact lens cleaners on the market today contain a surfactant and/or combination of surfactants, selected from the non-ionic, anionic or amphoteric categories. The use of a cationic surfactant in a contact lens cleaner is rare. Abrasives, or particulate matter in contact lens cleaners has been taught to assist the surfactant(s) in removal of soils. There have been reports in the contact lens industry that cleaners with harsh abrasives will change the power of rigid lenses over time due to a xe2x80x9cpolishingxe2x80x9d effect.
The cleaning process for contact lenses can be either active, digital rubbing of the lens surface, or passive, soaking the lens in the cleaning solution. These cleaning processes may be combined, that is, the contact lens is removed from the eye, digitally rubbed with the cleaning solution, then placed in that same cleaning solution overnight to allow passive cleaning to occur. Examples of this regimen for rigid lens would be the Boston Simplicity(copyright) solution and the Menicon Claris(copyright) system. For soft hydrogel lenses there are a number of products available that are considered multipurpose solutions, that is, cleaning, soaking and disinfection. Examples include Bausch and Lomb Renu(copyright), Alcon Optifree(copyright), Ciba Solocare(copyright) and Allergan Complete(copyright).
The surfactant(s) in contact lens cleaners serves a dual role. One role is to xe2x80x9csolubilizexe2x80x9d the soil on the lens into micelles. The other role is to xe2x80x9cdisplacexe2x80x9d the soil from the lens surface. This is accomplished by breaking the hydrophobic interaction between the soil and the lens surface, leading to a more thermodynamically preferred state. The use of abrasives help xe2x80x9cdisplacexe2x80x9d soils from the surface, thus aiding the surfactant(s).
Surfactant based contact lens cleaners on the market today vary in performance depending on the surfactant system chosen and the regiment recommended. For instance, surfactant/abrasive cleaners that are rinsed from the lens perform reasonably well, while multipurpose solution cleaners tend to be less effective due to the requirement that the cleaner be non irritating to the eye. Because soft hydrogel lenses have a rather porous structure, surfactants will tend to be absorbed into the lens structure, only to be released later into the ocular environment during lens wear.
Given the many types of contact lenses available today, i.e. low to high oxygen permeable rigid lenses, conventional and disposable hydrogel lens various water contents and surface charges, and the new soft silicone hydrogel lenses, there is a need for improved cleaning products and processes. The trend is toward more efficacious and convenient cleaning products that provide a margin of safety when used by the patient.
The present invention is based on the unexpected finding that the combination of a carboxylate containing anionic polymer, of molecular weight greater than about 1000 daltons, with cleaning agents, provides improved contact lens cleaning preparations. The cleaning process of the present invention includes contacting a soiled contact lens with an aqueous solution comprising an anionically charged polymer and a surfactant or surfactant combination selected from the classes of nonionic surfactants, anionic surfactants, and amphoteric surfactants.
The combination of anionic polymer with surfactant(s) may further comprise buffers and an antimicrobial compound. The subject preparations may be in the form of a stand alone cleaner to be used in combination with a wetting, soaking and disinfection solution. Alternatively, the subject preparations may be in the form of a one step cleaner that provides simultaneous disinfection and cleaning of contact lenses. In preferred embodiments of the present invention the subject preparations are utilized as cleaning solutions for rigid gas permeable lenses. Furthermore, in preferred embodiments the subject compositions also provide a one step cleaning regimen which utilizes only one solution for both cleaning and disinfecting soft hydrogel contact lenses. As such, the present invention offers distinct and significant advantages over known cleaning regimens for contact lenses.